Lithologic Controls on Geomorphic Evolution of the Central Western Ghats: An Example from the Aghnashini Catchment, Karnataka, India

Abstract

In spite of the prolonged exposure and denudation (for >50 Ma), the catchments of the Western Ghats escarpment depict significant relief and rugged topography along the Indian passive margin. In this study, an endeavour has been made to comprehend the function of lithology in landscape dynamics of the Aghanashini catchment through quantitative geomorphology. Longitudinal profiles of this catchment demonstrate disequilibrium through anomalous high stream gradient index and normalized steepness index (ksn) that are related to topographic breaks. Correlation between lithology types and ksn inferred predominant lithologic control on drainage disequilibrium. Transformed coordinate (χ-plot) of the longitudinal profile explained the knickpoint dynamics in an extensive manner where the outcomes suggested river capture process, formation of steep gorge, and series of hanging waterfalls due to sudden change in boundary conditions. This study indicates strong lithologic control under the influence of intense precipitation on shifting knickpoints throughout the catchment area forcing to maintain the valley relief and hillslope angles responsible for rugged and high relief topography of Aghnashini catchment of the Western Ghats.

Morphostructural influence and neotectonic activity in the geomorphological configuration of southeast Paraíba and northeast Pernambuco, Brazil

“…The SL index, formulated by Hack (1973) [ 33 ], quantifies the channel slope as a function of its downstream distance, offering insights into the longitudinal profile of rivers [ 34 ]. The SL was used to evaluate the intensity of tectonic events in the altimetric headwater/mouth configuration of fluvial channels.…”

Granite Weathering, Denudation Processes, and Associated Landforms in the Itu-Cabreúva Region, São Paulo, Brazil

“…Plate tectonics movement causes continental-scale deformation [4], while different climatic patterns play a crucial role in shaping the landform [5], leading to extensive erosion and sedimentation [6]. In such a scenario, lithological units act as building blocks for relief formation [7].…”

>i<Duricrusts>/i< ferruginosos e aluminosos e relações pedologia-geomorfologia-geologia no Alto Jequitinhonha (MG)

“…Por outro lado, quando essas superfícies atingem o equilíbrio, o intemperismo químico supera o físico, formando espessos perfis de intemperismo, incluindo os duricrusts. Seguindo essa concepção, por longo tempo considerou-se que os platôs mais elevados seriam mais antigos que os posicionados em elevações inferiores (Chorley, 1965), desconsiderando a possibilidade de rejuvenescimento topográfico por oscilações climáticas (p.e., Hancock e Kirwan, 2007), por litologias contrastantes (p.e., Das et al, 2022) ou pela reativação de antigas zonas de fraqueza através de epirogenia ou rebote isostático denudacional e flexural (p.e., Silva e Sacek, 2019;. A geocronologia do intemperismo utiliza-se da datação de minerais supérgenos precipitados nos perfis de intemperismo, de forma a correlacionar superfícies em escala local ou regional, ou ainda identificar a ordem cronológica evolutiva entre elas (Vasconcelos, 1998;Vasconcelos e Conroy, 2003;Vasconcelos e Carmo, 2018).…”